Electromagnetic transducers are known for use both in transforming electrical power into mechanical power and transforming mechanical power into electrical power. In both cases, power producing capability results due to relative movement between fields, as is well known, for example, in the application of this phenomenon to motors, alternators and generators.
While it is well known that motor, alternator and generator devices can be made that are quite light in weight, and while at least some known lightweight devices have been capable of operation at high speeds, such devices have not been capable of operation at high speeds to produce high power. For example, high power density devices of 0.6 horsepower per pound of weight are known for intermittent operation, but such devices are incapable of continuous operation at high power densities in excess of 1.0 horsepower per pound.
Known electromagnetic transducer devices have also not been capable of simultaneous high speed and high torque operation and/or have not provided adequate efficiency in operation. In addition, prior shell construction devices have not used both dispersed conductors and dispersed phase flux carrying means in the armature and have, therefore, also been limited to low speed, which, even at high torque, leads to low power density.
It is also well known that an electromagnetic transducer can include a stator and rotor arrangement, and that such an arrangement can include positioning magnetic elements on the rotor (see, for example, U.S. Pat. Nos. 3,663,850, 3,858,071, and 4,451,749), as well as on the stator (see, for example, U.S. Pat. Nos. 3,102,964, 3,312,846, and 3,602,749, 3,729,642 and 4,114,057). It has also been heretofore suggested that a double set of polar pieces could be utilized (see, for example, U.S. Pat. No. 4,517,484).
In addition, a shell type rotor has been heretofore suggested (see, for example, U.S. Pat. Nos. 295,368, 3,845,338 and 4,398,167), and a double shell rotor arrangement has also been suggested (see, for example, U.S. Pat. No. 3,134,037).
It has also been heretofore suggested that a bundle of wires can be utilized in place of a single conductor in the armature assembly of a motor (see, for example, U.S. Pat. Nos. 497,001, 1,227,185, 3,014,139, 3,128,402, 3,538,364 and 4,321,494, as well as British Patent No. 9,557) with such wires being stated to be for high voltage and high current usage and/or to reduce current flow loss, the so-called skin effect, and heating due to eddy currents, and with such wires being utilized in conjunction with solid and/or laminated cores (see, for example, U.S. Pat. Nos. 3,014,139, 3,128,402, and British Patent No. 9,557).
It has also been heretofore suggested that an electromagnetic transducer could have a power to weight ratio of up to about one horsepower to one pound (see, for example, U.S. Pat. No. 3,275,863). In addition, cooling of a motor, to increase power handling capability, using a gas, liquid, or a mixture of a gas and liquid, is well known (see, for example, U.S. Pat. No. 4,128,364).
While various arrangements for electromagnetic transducers have therefore been heretofore suggested and/or utilized, such transducers have not been found to be completely successful for at least some uses, including providing a lightweight transducer that is capable of providing high power.
In particular, the prior art does not teach the necessity to disperse the conductors to enable high speed operation, due, at least in part, to a widely taught theory that the magnetic field is very low in the conductors. With conductors built according to conventional teachings, however, it has been found that torque, at constant current, decreases with increasing speed, which result is contrary to the conventional expectation that torque would remain high as speed increases (which is the result achieved by this invention).
Prior art transducers are typically constructed such that the flux carrying elements are built up from laminated stacks of silicon steel, with heavy wire being wound directly in the wide, open slots between the laminated iron teeth. The tooth tips often cause wire breakage.
Conventional brushless DC motors up to six inches in diameter generally have a practical maximum of 36 laminated iron teeth. For a conventional three-phase motor, the number of slots per pole is three. Such motors have wedge or V-shaped slots (see FIG. 31) formed by the laminated teeth, with the result that the copper wires in the winding cannot be uniformly arranged such that the copper in some conductors (turns) cannot be located close to the iron teeth. For example, in a conventional six-inch diameter motor, the distance between the conductor farthest from the tooth (but inside the slot) is 0.158 inch. The resulting electromotive force (emf) induced in the turns of the coils is not at all uniform. This nonuniformity of emf requires circulating currents to be controlled by twisting the wires within the coil, resulting in less wire in the slot and more in the end turns and difficult manufacture.
Conventional motors also generally require a large number of turns per slot. This causes an increased reactive effect and large opposing magnetic fields. This results in greater degradation of power output.